Diet Drops Bladder-Infection Risk

Fresh berry juice, live yogurt linked to fewer urinary tract infections

From the WebMD Archives

Feb. 27, 2003 -- Women who drink lots of fresh berry juice -- and those who eat yogurt -- have a lower risk of bladder infections, a Finnish study shows.

The bad news: lots of sex increases bladder-infection risk for women.

Tero Kontiokari, MD, PhD, and colleagues at the University of Oulu, Finland, studied 139 30-something women with urinary tract infections. They compared them to 185 women of the same (or similar) age who hadn't had a bladder infection in at least five years.

"Dietary habits seem to be an important risk factor for urinary tract infection recurrence," the researchers report in the March 1 issue of the American Journal of Clinical Nutrition. "Dietary guidance could be a first step toward prevention."

For each glass of fresh fruit juice the women drank each day (up to three glasses), their risk of a bladder infection dropped by a third. But if they preferred fresh berry juice, their risk dropped by over two-thirds. What juices? Women showing protection drank fresh raspberry, lingonberry, strawberry, and currant juices. They also drank prepared raspberry, cranberry, and cloudberry juices. Since many of these berries were available only when in season, the researchers couldn't tell whether some berries were better than others.

Women who ate live-culture yogurt, sour cream, or live-culture cheese at least three times a week had a four-fifths lower risk of urinary tract infection.

As other studies have shown, having sex more often increased bladder-infection risk. In this study, sex three or more times per week increased infection risk nearly threefold over sex less than once a week.

What's happening? Berries are full of flavonols, compounds that make it hard for germs to stick to human cells. And live-culture milk products are full of friendly bacteria that can replace bad bacteria in the gut. However, the study does not prove this really happens. It could simply be that healthy people get fewer infections -- and that healthy people eat healthy foods such as berry juice and yogurt.